Coercivity in lean rare earth NdFeB and PrFeB nanocomposite hard magnetic materials
Coercivity in lean rare earth NdFeB and PrFeB nanocomposite hard magnetic materials
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贫稀土 NdFeB 和 PrFeB 纳米复合硬磁材料的矫顽力
DOI：
10.1016/s0925-8388(98)00761-0
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发表时间：
1998
影响因子：
6.2
通讯作者：
D. Givord
中科院分区：
文献类型：
--
作者：
S. David;D. Givord
采用溅射冷却法制备了交换弹簧型NdFeB和PrFeB纳米复合硬磁材料。磁滞周期表明，磁化过程可以分析的两个方面所产生的两个不同的阶段，存在于这些系统的贡献。软相磁化首先在约0.3 T的磁场下反转，发现该磁场与温度几乎没有关系。反射率由与硬相的交换耦合决定。晶粒尺寸为20 nm。该值与结构分析一致。硬相磁化反转在一个较大的字段值，这被发现是稳步增加，随着温度的降低（2.75 T的PrFeB样品和1.1 T的NdFeB样品在20 K）。Reversium被发现是由过程中，这是让人想起那些在通常的烧结或熔纺RFEB磁体的特征反转。在室温下，从磁后效测量推导出的活化体积为2200 nm 3。发现粒子间偶极相互作用对磁化反转的贡献很小。
NdFeB and PrFeB nanocomposite hard magnetic materials of the exchange-spring type were prepared by splat-cooling. Hysteresis cycles reveal that magnetisation processes may be analysed in terms of two contributions arising from the two different phases which exist in these systems. The soft phase magnetisation reverses first at a field of approximately 0.3 T which is found to be little temperature dependent. Reversal is determined by exchange coupling with the hard phase. A grain size of 20 nm is deduced. This value is in agreement with structural analysis. The hard-phase magnetisation reverses at a larger field value which is found to increase steadily with decreasing temperature (2.75 T in the PrFeB samples and 1.1 T in the NdFeB sample at 20 K). Reversal is found to be determined by processes which are reminiscent of those characterising reversal in usual sintered or melt-spun RFeB magnets. At room temperature, the activation volume deduced from magnetic after-effect measurements is 2200 nm3. The contribution of inter-particle dipole interactions to magnetisation reversal is found to be small.